East of England Ambulance Service NHS Trust (EEAST) crews were called to the A47 Broad End Road just after 6.30pm.

A spokeswoman said they assessed and treated five casualties in the single vehicle incident.

Crews worked hard to resuscitate two girls, aged around seven and 10, who had suffered serious head injuries but unfortunately they were declared deceased after arriving at Queen Elizabeth Hospital, King's Lynn.

A man and a woman and a boy aged about 12 suffered less serious injuries and were also taken to the QEH.

The EEAST spokeswoman said: "Crews worked hard in very difficult circumstances but despite sterling efforts they were sadly unable to save the two children This was an incredibly tragic incident and our deepest sympathies are with their family and loved ones."